A machine milks her three times a day. At her peak, she has given 156.4 pounds of milk daily. A transponder strapped to her right rear leg helps a computer track the precise sum of steps she takes per day.

Last year, two particular numbers bore down on her. After three attempts at artificial insemination failed over the course of 105 days, it became clear that something was amiss with the big black Holstein with the white forehead, legs and belly. If she did not get pregnant, her milk would begin to dry up.

The solution: inject her with Posilac, a genetically engineered growth hormone.

For two years, all the cows at Lagler Dairy in Brush Prairie, Wash., were injected with Posilac every two weeks. Milk production increased about 7 percent, but the added feed and injections were expensive. For the past three years, Dennis Lagler, owner of the Clark County dairy, has limited the hormone's use to specific cows such as No. 7775.

By Monday, though, Posilac may be finished at Lagler Dairy. Lagler and 146 other dairy owners connected by one of Oregon's oldest and most revered brands, the Tillamook County Creamery Association, are voting on what amounts to a referendum on Posilac's use.

The creamery's management and board of directors think Tillamook needs to wean itself from Posilac to satisfy consumers who worry about the effects of growth hormones on humans and cattle. Balancing consumer skittishness about biotechnology's health risks against the potential for greater farm production, the board has voted to end the hormone's use by Tillamook members.

Lagler, despite his reliance on Posilac, agrees with ending its use. His success depends on the value of the Tillamook brand, he says, and Tillamook's success is driven by consumers.

But Tillamook's board underestimated how much some member dairies were wed to Posilac. Those dairies have pushed back by calling for Monday's vote.

Tillamook's management thinks those dairies are being egged on by Monsanto, a corporation with $5.5 billion in annual sales and a history of filing lawsuits and shoveling money to squash threats against its use of biotechnology.

"We didn't want to be a target of Monsanto," said Jim McMullen, Tillamook's president and chief executive officer. "We have a great brand, and we're just trying to protect our reputation."

Monsanto, like the handful of dairy owners allied with the company who are willing to speak openly, says the cooperative is engaged in a struggle over individual rights within the cooperative.

"This is about the members of the co-op having a voice and their voice is not being heard," said dairy owner Kristina Radelfinger of Tillamook. She refused to say more.

Board votes for phase-out

Tillamook's nine-member board voted last May to phase out use of the hormone, requiring members to pledge to stop using Posilac by April 1, 2005.

McMullen said the decision was driven by consumer inquiries.

In 2002, he said, 3 percent of phone calls and e-mails received by the association were related to bovine growth hormones. That number rose to 4 percent the next year and hit 8 percent by 2004.

"Our research shows this is a top-of-the-mind issue for consumers," McMullen said.

For example, Dwight Porter, 37, a freelance photographer from Portland, said he stopped buying the Tillamook brand in December 2003. Porter, concerned that the federal government's review of Posilac had not adequately weighed human health risks, said he called to ask the cooperative about its growth-hormone policy.

In response, Tillamook sent him a form letter recounting the cooperative's dedication to quality and wholesomeness. The letter stated that it is impossible to test for the genetically modified hormone because it is indistinguishable from that naturally found in cows.

Tillamook heard few protests from dairy owners shortly after the May 2004 decision to phase out Posilac's use, McMullen said.

In November, the president of Monsanto's dairy arm wrote its Tillamook farm customers to say that restricting the hormone's use "seems ill-advised" because it would cut into dairies' choices and potentially their profits.

"I want you to know that Monsanto will work to ensure that you have a choice about how to run your dairy," Consuelo E. Madere wrote. "In our efforts to do this, it may be necessary for us to call on you to seek your advice."

In January, more than 80 dairy owners signed a petition asking the board to reconsider.

But after an additional discussion, the board reaffirmed its decision on Jan. 31. Steve Neahring, a board member and Nehalem dairyman, said the cooperative probably should have communicated better with members. Still, he said, the decision was sound.

"Sometimes things can get debated in a boardroom for a year or two, and you forget that all the membership wasn't along for the whole debate," he said. "But the most valuable asset the creamery owns is that brand."

The cooperative, founded in 1909, sells more than 100 million pounds of cheese a year nationally as well as milk and other dairy products. Its dairy sales in 2003 were $262 million.

Attorney delivers letter

Tillamook is no stranger to lawyers, having spent years warding off businesses it suspected were infringing on use of its name.

But McMullen, who thought the board's January affirmation had ended the Posilac fight, was surprised to discover Feb. 8 that a Washington, D.C., attorney had hand-delivered a two-page letter to Tillamook's corporate office.

The second page consisted of signatures from 16 members of the Tillamook cooperative. The first requested a full meeting of the members to amend the association's bylaws by adding this sentence:

" . . . the Board shall not in any way restrict the right of any member to use any pharmaceutical product approved by the United States Food & Drug Administration for use in dairy cattle."

The FDA approved Posilac's use in 1994 in one of the most oft-criticized decisions in its history because agency employees with former ties to Monsanto were involved. A later inquiry by what is now the Government Accountability Office then cleared them of violating conflict-of-interest law.

One former Monsanto researcher, for example, was asked to reach conclusions about whether artificial growth hormones could be detected in milk, even though she had done precisely the same work at Monsanto.

Another who came under the accountability office's scrutiny was Michael R. Taylor, who wrote the agency's guidelines on why milk produced by using growth hormones should not be labeled as such. Taylor has been a Monsanto vice president and a partner in King & Spalding, a firm that represents Monsanto.

The attorney who dropped off the letter seeking the Tillamook bylaw vote, James D. Miller, is also from the King & Spalding law firm. Miller did not return two phone calls seeking comment.

A spokeswoman for Monsanto, Jennifer Garrett, said Miller had worked for Monsanto on occasion but that "Monsanto is not paying him for his work in this Tillamook issue." Otherwise, Garrett said, Monsanto has not played a direct role in staging Monday's vote.

Monsanto already has played an influential role in shaping food policy in Oregon and the dairy industry elsewhere.

In November 2002, Oregon voters defeated a measure requiring labeling of genetically modified food, after Monsanto contributed more than one-fourth of the $5.5 million that helped defeat it.

The company also successfully sued a Maine dairy whose labels had proclaimed that it used no artificial growth hormones. In a 2003 settlement, the dairy had to add wording that the FDA had found no significant differences between milk from cows treated with artificial hormones and milk produced without them.

Tillamook's McMullen said the company intends to market its milk as free of artificial growth hormones but does not aim to change its labeling.

The cooperative's plans, however, hinge on how members vote Monday.

Posilac use tracked

Although Monsanto would not release market figures, a 2002 federal survey of dairies concluded that Posilac was being used on 22.3 percent of cows in 21 states. When the same study asked dairy owners why they were not using the hormone, cost and animal health were the most common reasons.

A panel convened by the Canadian Veterinary Medical Association in 1998 concluded that artificial hormones raised milk yield, but that cows developed udder infections at a 25 percent higher rate and ran a 50 percent higher risk of lameness in the feet and legs.

"Treated cows were at higher risk of being culled," the report noted.

Citing animal health concerns, the Canadian government in 1999 rejected Monsanto's attempts to win regulatory approval for Posilac.

Other studies indicate that the hormones don't measurably affect infection or cull rates of cows.

The anecdotal evidence is mixed as well. Dick Heathershaw, a Cloverdale dairyman, said cows treated with Posilac seemed to suffer more foot and leg problems as well as udder infections requiring treatment with antibiotics.

But Lagler said he saw no measurable difference in animal health when he treated his entire herd with Posilac.

As in the debate over food that is directly genetically modified, opponents have gathered inconclusive evidence about increased risks for cancer in humans and hormonal development in children.

Garrett of Monsanto replies: "Milk is milk. Our product works exactly the same as the (hormone) that the cow has on her own."

Cow No. 7775 was born Sept. 8, 1999, the product of artificial insemination. A number identifies her mother. Inside a computer, her father exists as a sequence of numbers and letters.

Without Posilac, her milk would have dried up and she would likely have gone where most dairy cows end up: to auction, the first stop on her way to a fast-food restaurant.

After 20 attempts while the cow continued to produce milk, No. 7775 finally became pregnant on Nov. 12 last year.

It's such cases, says dairywoman Carol Ann Leuthold of Tillamook, that should allow the continued use of Posilac. Her husband, David, signed the petition requesting Monday's vote because they want choices.

"We want the freedom to dairy the way we feel is best," she said.

"Tree-huggers would just as soon we didn't milk cows because they feel that is, shall we say, against nature. You don't wear pelts, you don't wear leather, you don't eat meat.

"I have a problem with quote-unquote tree huggers. We love our cows. We take care of our cows."